Pneumatic tire



May' 29, 1923.

W. E. POWERS E-r AL PNEUMATIC TIRE Fild May 1, 1922 l @wie f Patented May 29, 1923. l lA NETE@ STATES' PAT T GFFIC'.

WILLIAM E. POWERS, OF BOSTON, MART-IN F. HANNIGAN, F WATERTOWN, MASSACHUSETTS.

PNEUMATIC TIRE.

Application led Hay 1, 1922. Serial No. 557,528.

To all whom z't may concern.' the major portions of their external surfaces Be it known that we, WILLIAM E. POWERS being adapted to lbe united by vulcanizatioa and MARTIN F. HANNIGAN, citizens of the to the casings and the necks. The'beads are United States, residing at Boston and provided withabutment faces 16, extending Watertown, in the counties of Suffolk and (preferably obliquely) across the space be- 60 Middlesex, respectively, and State of Massatween the inner and outer facings.

chusetts, have invented new and useful Im- The shoe comprises also an inner tread provements in Pneumatic Tires, of which made of. a rubber composition, having the thefollowing is a specification. characteristics hereinafter described, and oc- This invention relates to the outer element cupying the space between the facings 12 and 65 or shoe of a pneumatic tire which includes a 13. lThe said inner tread has a relatively resilient inner element, suchas an inflatable thick central portion or -zone 17, and side inner tube enclosed in the shoe, the edges of portions 17a, extending from the central porthe shoe being beaded land adapted to be tion to the beads, and preferably decreasing interlocked with securing means on a wheel gradually in thickness from the central por- 7" rim, tion to the edges. The side ortions are pro- The chief object of the invention is to provided with edge faces 18, wliich conform to, vide a shoe of improved construction, elimand are abutted against, the bead faces 16. inating liability of rim-cuts and blow-outs, The shoe also comprises an outer tread,

20 and reducing to a minimum liability of sufmade of a relatively soft rubber composition 75 fciently puncturing the tread portion of which, when vulcanized, has the degree of the shoe to rupture the inner tube, resilience usually possessed by the tread of a The invention is embodied in the improvetire shoe. The outer tread has a relatively ments hereinafter described and claimed. thick central portion 19, and side portions Of the accompanying drawings forming a 19, covering theJ side portions of the outer 80 part of this specicatiomfacing 13, and gradually reduced in thick- Figure 1 is a transverse sectional view of ness from the central portion to the beaded the shoe member, called the inner tread. edge portions,

Figure 2 is a transverse sectional view The inner tread is molded and vulcanized showing one form of the entire shoe. separately, before it is incorporated in the 85 Figure 3 represents a sectional view of shoe. The rubber composition of which the an inner tread formed as an accessory of an inner tread is made, is characterized by the ordinary shoe. fact that it contains a greater percentage of Figure 4 is a sectional view showing the stii'ening or hardening ingredients, such as tread shown by Figure 3, in an ordlnaly sulphur and lime, than the composition of 9 shoe. which the outer tread is made. After the The same reference characters indicate the inner tread is molded, it is vulcanized to same parts in all of the figures. semi-hardness, so that although it has alim- In the embodiment shown by Figures 1 ited degree of flexibility and resilience, it is 40 and 2 our improved shoe comprises lamiconsiderably harder, andless flexible and 95 nated portions of fibrous material, composed resilient than the outer tread, its Ahardness either of sheets of textile fabric, or cords, or being such that it is adapted to better resist a combination of these, the fibrous vmaterial penetration by an instrumentality which beingv frictioned as usual, so that the elemay penetrate the outer tread. ments thereof may be united by vulcaniza- The facings 1 2 and 13, the necks 14,.and 100 tion. The said portions form a laminated the outer tread, are prepared for vulcaniza.- fibrous -inner facing or carcass 12, a lamition before the parts are assembled, and are nated fibrous outer facing or carcass 13, said vulcanized afterward. The final vulcanizfacings being spaced apart, and laminated. ing operation unites the outer and inner fibrous necks 14, connecting the edge por-` facings to the inner tread and to the beads,` tions of the facings, and forming therewith and unites the outer tread'to the outer facpockets containing the beads 15. The beads ing, and to a breaker strip 20, interposed may be of any suitable material or materials, between the central portions of the outer their form in cross section conforming to tread and the outer facing, said strip being no the confining means on the wheel rim, and at the same time united to the-outer facin The semi-hardness of the inner tread net only minimizes liability of puncturing said tread, and an inner tube within the shoe, but also eliminates all liabilit of rim-cuts and blow-outs. The side portion-s 17a of the inner tread constitutes relatively stiff struts, which extend to the beads and are supported by the bearing of the edge faces 18 on the abutment faces 16 of the beads. The side portions 17a are not suiciently flexible to enable them to be abruptly bentor buckled sidewise, but are sufiiciently flexble to enable them to cooperate with the resilient outer tread in imparting the desired riding qualities to the tire.

Figures 3 and 4 show an `inner tread', the central portion 27 and side portions 27 of which are formed externally to be inserted in a shoe of ordinary/construction, and composed, for example, of a laminated facing or carcass 28, and an outer tread of resilient rubber. composed of a central portion 29, and side portions 29, the edges of the shoe being provided with beads 30.

The inner tread is made of the same composition, and has the same characteristicsas the inner tread shown by Figures 1 and 2, and may be cemented to the inner surface of the facing 28 of an existing shoe, either before or after the shoe has been used. In this case the inner tread is an attachment, or accessory, which may be cemented to the internal surface of an ordinary shoe, and interposed between the inner surface of the latter and the inner tube. The application of the inner tread to a shoe as last described, will involve a reduction of the inner tube containing space, and the employment of a smaller inner tube. To prevent the objectionable friction and heat which would be developed by direct contact between the rubber inner tread and the rubber inner tube, we provide the inner surface of the inner tread with'an inner facing 31, of rubberized fabric, which contacts directly with the inner tube.

The inner tread having the described characteristics, constitutes a new article of manufacture, which may be incorporated in a shoe as a structural part during the manufacture thereof, or may be added to a complete shoe.

We claim:

1. A pneumatic tirecomprising an inner treadof rubber separately molded and vulcanized to semi-hardnss, and including side portions extending to the edge portions of the tire, a fibrous outer facing secured to the outer surface of the inner tread,and an accesos outer tread of relatively soft rubber secured to the outer surface of the outer facing, the semi-hardness of the -inner tread providing exemption from rim cuts and blow outs, and minimizing liability of puncture of the inner tread and of an enclosed inner tube.

2. A pneumatic tire comprising an inner tread lof rubber separately molded and vulcanized to semi-hardness, and including side portions extending to the edge portions of the tire, a fibrous inner facing secured to the inner surface of the inner tread, a fibrous outer facing secured to the outer surface of the inner tread, and an outer tread of relatively soft rubber secured to the outer surface of the outer facing, the semi-hardness of the inner tread providing exemption from rim v cuts and blow outs, and minimizin liability of puncture of the inner tread an of an enclosed inner tube.

3. A pneumatic tire comprising a laminated inner casing, a laminated outer cas'- ing, spaced from the inner casing, laminated necks connecting the edge portionsof said casings, and forming therewith beadcontaining pockets, beads occupying said pockets and having abutment faces extending across the space between said casings, an inner tread of semi-hard rubber interposed between said casings, and including side portions extending to said beads, the side portions having edge faces seated on said abutment faces, and an outer tread of relatively soft rubber covering the outer casing, the inner tread being separately molded and vulcanized to semi-hardness, and the said casings and outer tread being vulcanized on the inner tread, so that the casings, are united to the beads, the beads are united to the inner tread, and the outer tread is united to the outer'casing, by vulcanization', the semi-hardness of the inner tread providing exemption from rim cuts and blow-outs, and minimizing liability of puncture of the inner tread and of an enclosed in ner tube.

4. As an article of manufacture, an inner tread constituting a member of a tire shoe, and made of a semi-hard rubber composition molded and vulcanized, and formed to be interposed between an inner tube and the ex ternal surface of the shoe, said inner tread being provided with a facing of textile fabric secured to its inner surface.

ln testimony whereof we have affixed our signatures.

WILLXAM E. POWERS. MARTlN F. VNNGAN. 

